package com.xuecheng.base.utils;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import org.apache.commons.lang3.StringUtils;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.HashMap;

/**
 * @description 二维码生成工具
 * @author Mr.M
 * @date 2022/10/3 0:03
 * @version 1.0
 */
public class QRCodeUtil {
 /**
  * 生成二维码
  *
  * @param content 二维码对应的URL
  * @param width   二维码图片宽度
  * @param height  二维码图片高度
  * @return
  */
 public String createQRCode(String content, int width, int height) throws IOException {
  String resultImage = "";
  //除了尺寸，传入内容不能为空
  if (!StringUtils.isEmpty(content)) {
   ServletOutputStream stream = null;
   ByteArrayOutputStream os = new ByteArrayOutputStream();
   //二维码参数
   @SuppressWarnings("rawtypes")
   HashMap<EncodeHintType, Comparable> hints = new HashMap<>();
   //指定字符编码为“utf-8”
   hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
   //L M Q H四个纠错等级从低到高，指定二维码的纠错等级为M
   //纠错级别越高，可以修正的错误就越多，需要的纠错码的数量也变多，相应的二维吗可储存的数据就会减少
   hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
   //设置图片的边距
   hints.put(EncodeHintType.MARGIN, 1);

   try {
    //zxing生成二维码核心类
    QRCodeWriter writer = new QRCodeWriter();
    //把输入文本按照指定规则转成二维吗
    BitMatrix bitMatrix = writer.encode(content, BarcodeFormat.QR_CODE, width, height, hints);
    //生成二维码图片流
    BufferedImage bufferedImage = MatrixToImageWriter.toBufferedImage(bitMatrix);
    //输出流
    ImageIO.write(bufferedImage, "png", os);
    /**
     * 原生转码前面没有 data:image/png;base64 这些字段，返回给前端是无法被解析，所以加上前缀
     */
    resultImage = new String("data:image/png;base64," + EncryptUtil.encodeBase64(os.toByteArray()));
    return resultImage;
   } catch (Exception e) {
    e.printStackTrace();
    throw new RuntimeException("生成二维码出错");
   } finally {
    if (stream != null) {
     stream.flush();
     stream.close();
    }
   }
  }
  return null;
 }

 public static void main(String[] args) throws IOException {
  QRCodeUtil qrCodeUtil = new QRCodeUtil();
  System.out.println(qrCodeUtil.createQRCode("http://192.168.101.1:63030/orders/alipaytest", 200, 200));
 }
}